The purposes of this study were to (1) adapt an instrument “The Conceptions of Learning Science (COLS) questionnaire” into Turkish, and (2) to determine Turkish science teacher candidates’ COLS. Adapting the instrument four steps were followed. Firstly, COLS questionnaire was translated into Turkish. Secondly, COLS questionnaire was administered to science teacher candidates (n=382) from different universities in different regions of Turkey. After that, the exploratory factor analysis (EFA) was performed with 160 participants. Finally, the confirmatory factor analysis (CFA) was performed with remaining 219 participants. At the end of the validation processes six factors were retained. It was concluded that the adapted version of COLS questionnaire could produce valid and reliable scores on Turkish science teacher candidates.